A machine that can predict if you will go blind in your 60s by testing your eyes in your 20s is to be launched.

The Macuscope screens the macular pigment - the area at the centre of the retina that lets us see fine detail and colour - to pick up early warning signs of age-related macular degeneration (AMD).

Tom Bremridge, of The Macular Disease Society, said: "We welcome investment by opticians in this equipment."

Amd is the leading cause of blindness in the elderly. More than 500,000 people in the UK suffer from it and numbers are expected to soar in the next 25 years.